Supporting installations of the above type are used, for instance, in the foodstuff industry for supporting conveyor belts in compact air treatment plants, in which products arranged on the helically travelling conveyor belt are exposed to a flow of air. The flow of air can be adapted, for instance, to freeze or heat the product.
Air treatment plants of this type thus comprise a conveyor belt and a supporting installation. The conveyor belt is arranged in a helical path, the supporting installation being adapted to support the lowermost turn of the conveyor belt. In the contact surfaces between the conveyor belt and the supporting installation, relatively great, radially inwardly directed and vertically downwardly directed forces are applied, which cause frictional forces.
To reduce the frictional forces between the conveyor belt and the supporting installation it is known to arrange a slide bearing on the supporting installation, said slide bearing being capable of reducing the frictional forces caused by the vertical forces.
The drawbacks of such a solution are that it does not satisfactorily solve the problem with friction since relatively high frictional forces are still generated. Furthermore, this known solution is not capable of solving the problems that exist with regard to frictional forces caused by the radially inwardly directed forces which the conveyor belt exerts on the supporting installation.
SE 454,728 discloses a supporting installation, in which a bearing element containing balls is arranged between the conveyor belt and a section. The supporting installation comprises a chain on which the conveyor belt rests. The chain rests in turn on said balls, which thus are arranged in a channel defined by said chain together with the section, which forms a ball race. The balls act as a ball bearing between the conveyor belt and the section. Supporting installations comprising bearing elements in the form of balls are also known from U.S. Pat. No. 4,899,871 and U.S. Pat. No. 5,458,228.
There may in some cases be a need for supporting installations which have a higher capacity with regard to operating speed as well as load than the above-mentioned type of supporting installation with bearing elements in the form of balls.
U.S. Pat. No. 3,006,456 discloses a suspension device comprising a number of first and second pairs of wheels which are alternately arranged and connected to each other. The device is adapted to run in a square tube with a longitudinal slot. The first pairs of wheels each have an axle which via a link is adapted to be connected to an element that is to be suspended. The second pairs of wheels are perpendicularly arranged in relation to the first pairs of wheels.
It should be noted that the first and second pairs of wheels do not act as a bearing element.
A bearing element acts as a bearing between two parts, the bearing element being able to move independently of said parts.
There is thus a need for an improved supporting installation for supporting a helically travelling conveyor belt, said supporting installation having a higher capacity as regards operating speed and load.